evb@uic.edu

Retinoblastoma protein (pRB) provides the cell with the full potential of differentiation. We have identified the critical target of pRB in differentiation, RBP2 protein. Cells deficient in RBP2 have enhanced ability to execute differentiation program and override requirement of pRB for terminal differentiation. We have described promoters of several genes regulated by pRB and involved in differentiation progression as targets of regulation by RBP2. To gain insights into transcriptional regulation by RBP2, we are investigating recruitment of various chromatin factors on RBP2 target genes by using genome location analysis. RBP2 appears to form multiple protein complexes in mammalian cells, and we are especially interested in their role in differentiation. In addition, since RBP2 behaves as a potential oncogene we are currently developing mice models to study its role in transformation. Our studies are aimed on understanding the transcriptional regulation switch to differentiation and how pRB/RBP2 pathway contributes to promotion of differentiation.

pRB, first tumor suppressor protein described , is a critical regulator of cell cycle progression. Inactivation of pRB occurs at the point of cell cycle when cell makes a decision whether to continue to proliferate or to withdraw from the cell cycle to quiescence followed by senescence or differentiation. pRB activity changes in response to various extracellular stimuli, which represents a usual outcome of activation of signal transduction pathways. pRB interacts, both directly and indirectly, with transcriptional machinery leading to execution of a distinctive transcription program. The precise mechanism of how pRB acts to establish this program, however, is unknown.

Our studies suggest that in mammalian cells RBP2 (RBBP2/JARID1A) and pRB share a common, although sometimes opposing, role in regulation of differentiation. Not only they form protein complexes in vivo, but also act, at least in some cases directly, on the same target genes. Some of these targets, such as genes encoding BRD proteins, have been associated with cell fate determination, other targets, such as osteocalcin, have been connected to a specific stage of differentiation. RBP2 targets include to the vast extend promoters of genes encoding mitochondrial proteins or DNA-binding proteins. Comparison of RBP2 occupancy at different stages of monocytic differentiation showed stage-specific distribution across both categories of genes and correlated with the occurrence of hematopoietic transcription factors. Recent discoveries in the enzymology of chromatin show that RBP2 possesses multiple signature motifs that potentially direct its binding to methylated chromatin. We are looking for the constituents of RBP2 complexes that are important for its effects on transcription. The results of our studies suggest that the interaction of pRB with RBP2 provides a general control over cellular decision whether to withdraw from the cell cycle and differentiate.

RBP2 family proteins have been associated with human malignancies. While a RBP2 gene translocation has been described in a child with acute myeloid leukemia, the RBP2 homolog PLU-1 is a cancer specific antigen overexpressed in the majority of breast cancer cases. We are currently developing RBP2 and PLU-1 mice models that will be useful to study the role of RBP2 protein family in pRB-mediated differentiation and in cellular transformation.

Selected Publications:

Kaelin, W. G. Jr, T. Volkert, H.L. Murray, R. A. Young, and E.V. Benevolenskaya. 2006. RBP2 target genes reveal genetic network controlling differentiation. In preparation.

Benevolenskaya, E.V., H.L. Murray, P. Branton, R.A. Young, and W.G. Kaelin, Jr.. 2005. Binding of pRB to the PHD protein RBP2 promotes cellular differentiation. Molecular Cell 18: 623-635.

Preview by Gutierrez, G.M., E. Kong, and P.W. Hinds “Master or slave: the complex relationship of RBP2 and pRb” in 2005 Cancer Cell 501-502.

Serebriiskii, I.G., O. Mitina, E.N. Pugacheva, E.V. Benevolenskaya, E. Kotova, G.G. Toby, V. Khazak, W.G. Kaelin, J. Chernoff, and E.A. Golemis. 2002. Detection of peptides, proteins, and drugs that selectively interact with protein targets. Genome Research 12: 1785-1791.

Frolov, M.V., E.V. Benevolenskaya, and J.A. Birchler. 2001. Molecular analysis of a novel Drosophila diacylglycerol kinase, DGKe. Biochimica & Biophysica Acta 1538: 339-352.

Frolov, M.V., E.V. Benevolenskaya, and J.A. Birchler. 2000. The oxen gene of Drosophila encodes a homolog of subunit 9 of yeast ubiquinol-cytochrome c oxidoreductase complex: evidence for modulation of gene expression in response to mitochondrial activity. Genetics 156: 1727-1736.

Benevolenskaya, E.V., M.V. Frolov, and J.A. Birchler. 2000. Krüppel homolog (Kr h) is a dosage-dependent modifier of gene expression in Drosophila. Genetical Research 75: 137-142.

Benevolenskaya, E.V., M.V. Frolov, and J.A. Birchler. 1998. The sugarless mutation affects the expression of the white eye color gene in Drosophila melanogaster. Molecular & General Genetics 260: 131-143.

Nurminsky, D.I., M.V. Nurminskaya, E.V. Benevolenskaya, Y.Y. Shevelyov, D.L. Hartl, and V.A. Gvozdev. 1998. Cytoplasmic dynein intermediate chain isoforms with different targeting properties created by tissue-specific alternative splicing. Molecular and Cellular Biology 18:6816-6825.

Benevolenskaya, E.V., G.L. Kogan, A.V. Tulin, D. Philipp, and V.A. Gvozdev. 1997. Segmented gene conversion as a mechanism of correction of 18S rRNA pseudogene located outside of rDNA cluster in D. melanogaster. Journal of Molecular Evolution 44: 646-651.

Benevolenskaya, E.V., D.I. Nurminsky, and V.A. Gvozdev. 1995. Structure of the Drosophila melanogaster annexin X gene. DNA and Cellular Biology 14: 349-356.

Benevolenskaya, E.V., G.L. Kogan, M.D. Balakireva, D. Filipp, I.P. Arman, and V.A. Gvozdev. 1994. Analysis of pseudogene nucleotide sequence reveals variability of rDNA genes in Drosophila melanogaster. Genetika 30: 280-286.

Dr. Elizaveta Benevelonskaya, Assistant Professor

PhD Moscow State University, Russia
(advisor Dr. Vladimir Gvozdev)

Post-doc University of Missouri-Columbia
(advisor Dr. James Birchler)

Res. Associate Harvard Medical School &
Dana-Farber Cancer Institute
(advisor Dr. William Kaelin, Jr.)